Lost amid all the talk about millionaires influencing the 2012 election is a striking fact: The Republican primaries are shaping up as the cheapest and most financially depressed presidential nominating contests in years.

Former Massachusetts governor Mitt Romney and the other Republicans vying to take on President Obama in November have raised and spent about half as much money as the GOP field did four years ago, campaign disclosure data show. The trend doesn’t stop there: Republicans in 2000 and Democrats in 2004 posted stronger financial numbers than this year’s crop of GOP challengers have.

Even adding this year’s spending by super PACs — a new kind of independent group that can raise millions of dollars at a time — the Republican contenders spent more cash in 2008 all on their own.

The numbers, tallied through the end of January, complicate the widespread portrait of the 2012 campaign as an example of political spending run amok. While many voters may feel overrun with negative ads, every primary season since the 1990s has featured more spending than the current contest, records show.

The totals also underscore a persistent enthusiasm problem that has dogged this year’s GOP presidential hopefuls, most of whom haven’t come close to raising as much money as the top candidates did in 2008. Romney, despite being the presumed front-runner, has actually brought in donations at a slightly slower pace than he did four years ago, when he was considered an underdog in a well-funded field that included a veteran U.S. senator and a former New York mayor.

Even Obama, who does not have to fight a primary opponent, has begun to lag behind the pace he set in 2008, when he became the most successful fundraiser in U.S. political history.

Strategists, fundraisers and campaign-finance experts offer a variety of explanations for the tepid fundraising, including a weak economy that has strained donors’ bank accounts and, on the Republican side, a more extended primary season. But most agree that the biggest reason appears to be a lack of excitement among Republican donors at all income levels, many of whom have remained on the sidelines as the GOP primary battle drags on.

“The most important factor has just been the weakness of the Republican field,” said Anthony Corrado, a campaign finance expert at Colby College in Waterville, Maine. “You did not have candidates run that were well-known, with well-established bases of financial support. . . . Even with the super PACs, this is not a race where you’ve seen record amounts of money being spent.”

Surge still expected

Few expect the fundraising drought to last into the general-election campaign, which still appears likely to rank among the most expensive ever. Once the Republican nominee is chosen, most strategists predict, party donors will quickly rally around the candidate and produce a surge of money to go up against the Obama campaign. The surge will be augmented by money from super PACs and other outside groups, which will have an easier time raising money than they did in previous election cycles.

Even then, however, the slow primary fundraising — and the high spending necessary to keep fighting for the nomination — will present Republicans with a steep financial hill to climb. Obama reported having $76 million in cash on hand at the end of January, not counting tens of millions more being stockpiled by the Democratic National Committee.

“Mitt Romney is gaining people’s respect, but not their passion and not their love,” said Michael Malbin of the Campaign Finance Institute, which studies donors and contribution patterns in political races. “It will have to be a passion against the president rather than for the candidate that brings the numbers up.”

In 2008, the combined Republican field — led by Romney, Sen. John McCain (Ariz.) and former New York mayor Rudolph W. Giuliani — had raised nearly $310 million and spent $278 million of that through the early January contests, according to data from Malbin’s research. The figures include $42 million in money that Romney poured into the race from his personal bank account.

Those numbers have been halved in 2012, with $146 million raised and $133 million spent by GOP presidential candidates through Jan. 31, the data show. Romney has not contributed his own money this time around.

This year’s crop of hopefuls does have a new financial weapon in the form of super PACs, which are technically separate from the campaigns but can raise unlimited amounts of money on their behalf. The groups have had an inordinate influence on the primary race by dominating ad spending in many of the early primary states and helping to keep such long-shot contenders as Newt Gingrich in the game.

Nonetheless, even the monied super PACs haven’t closed the gap in spending compared with 2008. The top six GOP super PACs spent about $37 million on behalf of their favored presidential candidates through January, according to Federal Election Commission data.

Super PACs’ impact

David Donnelly, executive director of the Public Campaign Action Fund, which favors public financing of campaigns, noted that weak fundraising by candidates has served to amplify the impact of super PACs, which would have had much less influence if they had existed in 2008.

“There seems to be very little excitement among voters in the donor class about these candidates,” Donnelly said. “What that gets replaced with is this new phenomenon of people writing huge checks in support of the candidates. You’re replacing excitement with those who have a huge amount of money.”

Candidates have yet to report their official February fundraising totals to the FEC, but all signs point to another modest month. The Romney campaign has said it raised $11.5 million and spent about as much, while former senator Rick Santorum (Pa.) says he raised $9 million on the strength of several primary victories.

During the same month in 2008, by comparison, Obama brought in $57 million and had $39 million in cash on hand heading into March during his epic primary battle with then-Sen. Hillary Rodham Clinton (D-N.Y.), FEC reports show. Obama is unlikely to come anywhere close to that total in this campaign.

The surge of spending by super PACs this year has prompted calls for greater restrictions on such groups, which were ushered into existence by a series of court rulings that upended decades of campaign-finance regulations.

But Bradley A. Smith, a former FEC chairman who heads the Center for Competitive Politics, which opposes many campaign-finance regulations, said the relatively low fundraising and spending levels this year suggest that the criticism is misplaced.

“Much of the outcry over these decisions really is not warranted,” Smith said. “The idea that we would be awash and drowning in political ads has not really come true.”

Staff writer T.W. Farnam contributed to this report.